title	Kaypro 4-83 Resident Software Package
subttl	Disk Equate and Parameters
;
; ################################################################
; ##								##
; ##	Disk support routines					##
; ##								##
; ################################################################
; ##	Last Update:06/08/82		[001]			##
; ################################################################
; #	Revised to KPRO4, 3 Mar. 1984, C.B. Falconer		##
; ################################################################
; ## Revised for integral data segment with Z80ASM  85/6/15 cbf ##
; ## General purpose disk routines, reduced Ram use.  Avoid use ##
; ## of AF' register (reserved for other uses).  Added use of   ##
; ## register E for drive sensing, per CPM standards.  Added    ##
; ## provision for disabling write checking.  Re-organized.     ##
; ## The "home" routine now returns a pointer to a data area.   ##
; ## Note the unmodified Kaypro returns a pointer in page zero, ##
; ## so software can tell them apart.				##
; ################################################################
; ## 85/6/18 cbf. Added disk error messages, corrected summary  ##
; ## reset on any cold boot via diskinit.  Reduced error retrys ##
; ################################################################
;
	extrn	bitport, bankbit;	bank selection
	extrn	.thnsd;			delay
	extrn	.print, .vidout;	for error system
;
; linkage to deblocking system
	extrn	erflag, unacnt
	extrn	hstact, hstbuf, hstdsk
	extrn	hstsec, hsttrk, hstwrt
;
	entry	home, seldsk, settrk, setsec
	entry	sectran
	entry	diskinit, datainit, diskon, diskoff
	entry	readhst, writehst
;
; Public data areas (for deblocking area)
	entry	sekdsk, seksec, sektrk
	entry	denflag
;
; Entries to installed routines in data segment
	entry	move, rd, wrt
;
; ---------------------------------------------------------
;
drvmask	equ	0FCH;		drive select mask
denmask	equ	0DFH;		density bit mask
ddbit	equ	00H;		double density bit
sdbit	equ	20H;		single density bit
sidebit	equ	4;
mtroff	equ	40h
;
; Disk controller ports
control	equ	10H;		I/O port of disk controller
status	equ	control+0;	status register
cmnd	equ	control+0;	command register
track	equ	control+1;	track register
sector	equ	control+2;	sector register
data	equ	control+3;	data register
;
; Controller commands (selected)
ficmd	equ	11010000B;	force interrupt (Abort current command)
rdcmd	equ	10001000B;	read command
wrtcmd	equ	10101100B;	write command
seekcmd	equ	00010000B;	seek command
rstcmd	equ	00000000B;	home (restore) command
adrcmd	equ	11000100B;	read track address
rdmask	equ	10011100B;	read status mask
wrtmask	equ	11111100B;	write status mask
;
; retry control
tries1	equ	3;		re-home on bad sector # of tries+1
tries2	equ	6;		re-read/write # of retries+1
;
; Miscellaneous
retcod	equ	0C9H;		return op code
nmivec	equ	0066H;		non-maskable interupt vector
esc	equ	01bh;		for error message positioning
;
subttl Physical disk routines
;
	cseg
;
; enter here on system boot to initialize
; a,f,b,c,d,e,h,l
diskinit:
	ld	hl,ioimage;	move rd/wrt/dphs routines into RAM
	ld	de,move
	ld	bc,imaglen
	ldir
;
	xor	a;		0 to accumulator
	ld	(hstact),a;	host buffer inactive
	ld	(unacnt),a;	clear unalloc count
	ld	a,ddbit;	set double density flag
	ld	(denflag),a
	ld	a,255;		set track numbers to 255
	ld	(dsk),a;	clear disk number
	ld	(tracka),a
	ld	(trackb),a
	ret
;
; called on cold start to initialize error counts etc
; f,b,c,d,e,h,l
datainit:
	ld	hl,.ckwrt
	ld	de,chkwrt
	ld	bc,.ckend-.ckwrt
	ldir
	ret

;
; perform logical to physical sector translation.
; logical sector number in BC, table address in DE
; return physical sector number in HL
; a,f,d,e,h,l
sectran:
	ld	a,d;		table address 0?
	or	e
	ld	h,b;		if so no xlate
	ld	l,c
	ret	z
	ex	de,hl;		table address in hl
	add	hl,bc;		index by logical sector number
	ld	l,(hl)
	ld	h,0
	ret
;
; set sector given by register c 
; a,f
setsec:	ld	a,c
	ld	(seksec),a;	sector to seek
	ld	a,(denflag)
	or 	a
	ret	z;		single density
;	"	"
; select sector #, BC=Sector # (double density)
; a,f
secset:	in	a,(bitport);	single or double sided?
	and	sidebit
	ld	a,c;		move sector number to A
	jp	z,secst1;	pure sector no in single sided
	add	a,10
secst1:	out	(sector),a;	to controller register
	ret
;
; Set track
settrk:	ld	h,b
	ld	l,c
	ld	(sektrk),hl;	set track given by registers BC
	ld	a,(denflag)
	or 	a
	ret	z;		single density
;	"	"
; seek track #, BC=Track # (double density)
trkset:	call	ready;		make sure drive is on and ready
	ld	a,(sidflg);					{}
	or	a
	jp	z,tkset3;	single sided, select side 0
	ld	a,c;		else double sided drive
	rra;			trk no divided /2
	ld	c,a;		for actual selection
	in	a,(bitport)
	jp	c,tkset1;	and select side 0 for even track
	and	not sidebit;	else select side 1
	jp	tkset2
tkset1:	or	sidebit
tkset2:	out	(bitport),a;	select side
tkset3:	ld	a,c;		get physical track number
	ld	(ctrack),a
	out	(data),a;	track # to seek to
	ld	a,seekcmd;	seek command
	out	(cmnd),a;	issue command
;	"	"
; check status of controller, wait for command to finish executing
; a,f
busy:	ld	a,(nmivec)
	push	af
	ld	a,retcod
	ld	(nmivec),a
	halt;			wait for command done
	pop	af
	ld	(nmivec),a
busy1:	in	a,(status);	now wait for not busy
	bit	0,a;		preserve code to return
	jp	nz,busy1
	ret
;
; home disk
; a,f,h,l
home:	ld	a,(denflag)
	or 	a
	jp	nz,dohome;	double density
	ld	a,(hstwrt);	patch by DRI
	or	a
	jp	nz,dohome
	ld	(hstact),a
;	"	"
; home disk head
dohome:	call	ready;		make sure drive is on and ready
	in	a,(bitport)
	and	not sidebit
	out	(bitport),a;	select side 0
	xor	a
	ld	(ctrack),a;	reset current track number
	ld	a,rstcmd;	restore command
	out	(cmnd),a;	issue command
	call	busy;		test and wait for not busy
	ld	hl,chkwrt
	ret
;
; select disk
seldsk:	ld	a,c;		selected disk number
	ld	(sekdsk),a;	seek disk number
;	"	"
; Physical disk drive select, C=drive number 0=A:, 1=B:
; return HL=dph for selected drive, or HL=0 for non-existent drive
; Set up density for ddrive selected
dsksel:	ld	hl,0;		hl = 0 for non-existent drive
	ld	a,c
	cp	2
	ret	nc;		drive number >B:
	or	a;		z flag set => A: drive else B: drive
	ld	a,e;		Save the CPM flag momentarily
	ld	de,tracka;	find propert track(x) and..
	ld	hl,dpha;	select proper dph for drive
	jp	z,sel0
	ld	de,trackb
	ld	hl,dphb
sel0:	push	hl;		save dph of disk to be selected
	and	1
	ld	a,(dsk)
	jp	nz,sel0a;	Previously selected to CPM
	ld	a,255
	ld	(de),a;		Mark for sensing
	xor	a
	ld	(unacnt),a;	home will reset hstact on sense
	ld	a,(dsk)
	cp	c
	jp	z,selnot;	reselecting the current disk
sel0a:	cp	c;		selecting disk already selected?
	jp	z,selx;		yes, no further action needed
	ld	a,c;		save new disk number
	ld	(dsk),a
	or	a;		set zero flag if A: drive
	ld	hl,ctrack
	ld	de,trackb;	now find proper track(x)
	jp	z,sel1
	ld	de,tracka
sel1:	ld	a,(de);		have we been on disk we're "leaving"
	cp	255;		if not do not update tracks
	jp	z,selnot
	push	bc
	ld	bc,3
	ldir;			save old table
	pop	bc
selnot:	ld	de,ctrack;	now to update main table  {}
	ld	a,c;		set z flag if A: drive
	or	a 
	ld	hl,tracka
	jp	z,sel2
	ld	hl,trackb
sel2:	ld	a,(hl)
	cp	255;		first time for this drive?
	jp	z,density;	if so, go set it up
	ld	bc,3
	ldir;			init table for density
	ld	bc,15;		dparm size
	ld	de,dpbd;	dparm addr
	ld	hl,.dpbd;	single sided table
	ld	a,(sidflg)
	or	a
	jp	z,sel2a
	ld	hl,.dsdd;	double sided table
sel2a:	ldir;			move in dparm for this drive
	ld	a,(ctrack)
	out	(track),a
selx:	pop	hl;		adr of dph for disk we are selecting
	ret
;
density:
	ld	a,ddbit
	ld	(denflag),a
	call	ready;		physical disk select
	call	home;		seek track 0, side 0
	pop	hl
	call	dcheck;		see if we can read address
	jp	z,dend;		if so, density is double
	ld	a,sdbit
	ld	(denflag),a
	call	ready;		try single density
	call 	dcheck
	ret	nz;		can't read, so don't change
;	"	"
; set up for single density operations
	push	hl;		(* single density *)   hl^ to dph
	push	de
	ld	de,tbl1;	single density sector xlate table
	ld	(hl),e;		store table^ into dph
	inc	hl
	ld	(hl),d
	ld	de,9;		move foward in dph to dpb pointer
	add	hl,de
	ld	de,dpbs;	single density dpb
	ld	(hl),e
	inc	hl
	ld	(hl),d;					{}
	jp	den1
;
; set up for double density operations
dend:	push	hl;		(* double density *)   hl^ to dph
	push	de
	ld	de,0;		no xlate table (done by FORMAT prog)
	ld	(hl),e;		store table^ into dph
	inc	hl
	ld	(hl),d
	ld	de,9;		move forward in dph to dpb pointer
	add	hl,de
	ld	de,dpbd;	double density dpb
	ld	(hl),e
	inc	hl
	ld	(hl),d
	in	a,(bitport);	now try side 1 (double sided?)
	or	sidebit
	out	(bitport),a;	select side 1
	call	dcheck;		try to read it
	ld	bc,15
	ld	de,dpbd
	ld	hl,.dpbd;	source, single sided dparm
	ld	a,0;		single sided flag (dont chg flags)
	jp	nz,selsid;	single sided if not zero.
	ld	a,(dsksns+2);	is sector # > 9
	cp	10;		 (it must be for valid dbl sided op)
	ld	a,0;		 (if not, single sided drives)
	jp	c,selsid;	select single sided
	ld	hl,.dsdd;	source double sided dparm
	ld	a,255;		proper sidflg
selsid:	ld	(sidflg),a;	set up double density dparm    {}
	ldir
	in	a,(bitport);	return to size zero
	and	not sidebit
	out	(bitport),a 
;	"	"		exit
den1:	ld	hl,ctrack
	ld	de,tracka
	ld	a,(dsk)
	or	a
	jp	z,dskupd;	update dsk trk, side, etc. table
	ld	de,trackb
dskupd:	push	bc
	ld	bc,3
	ldir
	pop	bc
	pop	de;		restore pointer to dph
	pop	hl;		pointer to track(x) bios register
	ret
;
; check disk legible at current format. z flag if so
; a,f
dcheck:	push	hl
	push	bc
	ld	hl,dsksns
	ld	bc,6*256+data;	6 bytes from adr. header via "data"
	ld	a,(nmivec)
	push	af
	ld	a,retcod
	ld	(nmivec),a
	ld	a,adrcmd;	get address command
	out	(cmnd),a;	issue command to controller
dchk1:	halt;			await interrupt from controller
	ini
	jp	nz,dchk1
	pop	af
	ld	(nmivec),a
	call	busy;		wait for command done
	and	10h;		record not found flag
	pop	bc
	pop	hl
	ret;			return status
;
; ready disk drive, perform physical disk select, set density bit
; a,f
ready:	push	hl;		save hl
	push	de;		and de
	push	bc
	ld	a,ficmd;	abort any controller action
	out	(cmnd),a
	call	diskon;		turn drive motor on
	ld	a,(dsk);	A=drive #
	ld	e,a;		save drive # in E
	in	a,(bitport);	A=bit port
	and	drvmask and denmask;	strip drive/density bits
	or	e;		or in requested drive
	inc	a;		bump, 01=A:    10=B:
	ld	hl,denflag;	hl^ to density bit for this drive
	or	(hl)
	out	(bitport),a;	to bit port
	pop	bc
	pop	de
	pop	hl
	ret
;
; turn disk motor on, delay for drive speed
; a,f,b		(because .thnsd protected)
diskon:	in	a,(bitport);	get current drive motor status
	bit	6,a;		is motor on? (save other bits)
	ret	z;		motor on, do nothing
	and	not mtroff;	motor on bit
	out	(bitport),a;	turn motor on
	ld	b,50;		delay 1/2 second & exit
	jp	.thnsd
;
; turn disk motor off
; a,f
diskoff:
	in	a,(bitport)
	or	mtroff;		motor off bit
	out	(bitport),a
	ret
;
subttl Writehst and Readhst logical to Physical routines
;*	WRITEHST performs the physical write to      *;
;*	the host disk, READHST reads the physical    *;
;*	disk.					     *;
;
; hstdsk = host disk #, hsttrk = host track #,
; hstsec = host sect #. write "hstsiz" bytes
; from hstbuf and return error flag in erflag.
; return erflag non-zero if error
writehst:
	ld	l,3;		readback retries
wthst0:	ld	a,(rtry1)
	ld	d,a;		reseek tries
wthst1:	ld	a,(rtry2)
	ld	e,a;		retry error counts
wthst2:	push	hl
	push	de;		save error counts
	call	hstcom;		set track and sector
	ld	de,hstbuf
	ld	b,4;		record sector
	call	wrt;		write sector into hstbuf
	pop	de;		restore error flags
	pop	hl
	jp	z,wtchk;	good op
	dec	e;		retry count
	jp	nz,wthst2;	try again
	dec	d;		home and reseek count
	jp 	z,wtchk3;	can't recover
	push	hl
	call	dohome;		re seek
	pop	hl
	jp	wthst1;		reset retry count
;
; Read back the sector to check CRC for a good write
wtchk:	ld	a,(chkwrt)
	or	a
	ret	z;		write checking disabled
	ld	b,0
	in	a,(nmivec)
	push	af
	ld	a,retcod
	ld	(nmivec),a
	ld	a,rdcmd;	read it back to check CRC
	out	(cmnd),a
wtchk1:	halt
	in	a,(data)
	djnz	wtchk1
wtchk2:	halt
	in	a,(data)
	djnz	wtchk2
	pop	af
	ld	(nmivec),a
	call	busy
	and 	rdmask
	call	nz,saverr;	record any soft errors
wtchk3:	ld	(erflag),a
	call	errmsg;		saves regs/flags, msg if a <> 0
	ret	z;		either good or entry from wthst
	dec	l
	jp	nz,wthst0;	try again
	ret;			with hardware error flags
;
; hstdsk = host disk #, hsttrk = host track #,
; hstsec = host sect #. read "hstsiz" bytes
; into hstbuf and return error flag in erflag.
readhst:
	ld	a,(rtry1)
	ld	d,a
rdhst1:	ld	a,(rtry2)
	ld	e,a;		retry error counts
rdhst2:	push	de;		save error counts
	call	hstcom;		set track and sector
	ld	de,hstbuf
	ld	b,4;		record sector
	call	rd;		read sector into hostbuf
	ld	(erflag),a;	error return flag
	pop	de;		restore error flags
	ret	z;		good op
	dec	e;		retry count
	jp	nz,rdhst2;	try again
	dec	d;		home and reseek count
	call	z,errmsg;	saves regs/flags, message if a<>0
	ret	z;		can't recover
	call	dohome;		re seek
	jp	rdhst1;		reset retry count
;
hstcom:	ld	a,(hstdsk);	select disk
	ld	c,a
	ld	e,1;		NOT a CPM call, dont force sensing
	call	dsksel
	ld	hl,(hsttrk);	set track to hsttrk
	ld	b,h;		 one byte more than "ld bc,", and
	ld	c,l;		 easily tracked with ddt etc.
	call	trkset;		physical seek
	ld	a,(hstsec);	set physical sector
	ld	c,a;		c=sector
	jp	secset;		and exit
;
; show error details if a <> 0
errmsg:	push	af
	or	a
	jp	z,errmsgx;	all well
;	"	"
; Show disk, track, sector, error kind.
; Must save and restore cursor position.
; This can foul the screen if it occurs in the midst of
; an escape sequence from the application program.
	push	bc
	push	de
	push	hl
	ld	c,esc
	call	.vidout;	separate, to get orig. cursor
	push	hl;		save cursor
	ld	de,posn
	call	.print;		position to error msg location
;	"	"
; all positioned, now we can write the error details
	ld	a,(dsk)
	add	'A'
	ld	c,a
	call	.vidout
	ld	de,part2
	call	.print
	ld	a,(hsttrk)
	call	decout
	ld	de,part3
	call	.print
	ld	a,(hstsec)
	call	decout
	ld	a,(erflag)
	ld	hl,errids-5
	ld	de,5
erm1:	add	hl,de;		at least one bit must be set
	rlca
	jp	nc,erm1;	find appropriate message
	ex	de,hl
	call	.print
;	"	"
; restore the original cursor position
	ld	c,esc
	call	.vidout
	ld	c,'='
	call	.vidout
	pop	hl
	push	hl
	ld	c,h;		the original "y"
	call	.vidout
	pop	bc;		and the original "x"
	call	.vidout
	pop	hl
	pop	de
	pop	bc
errmsgx:
	pop	af
	ret
;
posn:	db	'=', 23+' ', 64+' ',0;	leaving 16 char msg space
part2:	db	': T',0
part3:	db	', S',0
errids:	db	' NRY',0;	bit 7 - not ready
	db	' WPR',0;	    6 - write protect
	db	' WFT',0;	    5 - write fault
	db	' RNF',0;	    4 - record not found
	db	' CRC',0;	    3 - CRC error
	db	' LDA',0;	    2 - data overrun
	db	' DRQ',0;	    1 - data not supplied
	db	' BSY',0;	bit 0 - not ready
;
; output (a) as 2 digit decimal no.
; a,f,c,h,l
decout:	ld	c,'0'-1
dco1:	inc	c
	sub	10
	jp	nc,dco1
	push	af
	ld	a,'0'
	cp	c
	call	nz,.vidout;	suppress leading zero
	pop	af
	add	'0'+10
	ld	c,a
	jp	.vidout
;
; save and record soft error counts. Save regs.
saverr:	push	hl
	push	af;		the error
	ld	a,(dsk)
	ld	hl,aerr
	or	a
	jp	z,saver1;	a drive
	inc	hl
	inc	hl;		b drive, advance pointer
	inc	hl
saver1:	pop	af
	push	af
	ld	(hl),a
	inc	hl
	inc	(hl);		count the error
	jp	nz,saver2;	no carry
	inc	hl
	inc	(hl)
saver2:	pop	af
	pop	hl
	ret
;
subttl Physical disk I/O, RAM image
;
ioimage:
; This area is moved to memory for execution.
; All jumps must be relative for position independance
;
; block memory move, turn rom on/off
.move:	in	a,(bitport);	turn rom off
	and	not bankbit
	out	(bitport),a
	ldir;			move logical sector from hstbuf
	in	a,(bitport);	turn rom back on
	or	bankbit
	out	(bitport),a
	ret;			back to rom
;
; read a sector into de^
; return	A=0 for no errors,
;		A=1 for non-recoverable error
; if b=1 128, b=2 256, b=3 384, b=4 512   bytes/sector
.rd:	ld	hl,rdmask*256+rdcmd;	d=read status mask
	jr	action;			e=read command
;
; write a sector from de^
; return as per read from de^.
; b is sector length in 128 byte records
.wrt:	ld	hl,wrtmask*256+wrtcmd;	d=status mask, 
;	"	"			e=write command
;	"	"
action:	ex	de,hl
	call	ready;		make sure drive is on and ready
	di;			no interrupts during disk I/O
	in	a,(bitport);	turn rom off
	and	not bankbit
	out	(bitport),a
	ld	a,(nmivec)
	push	af
	ld	a,retcod
	ld	(nmivec),a;	set up nmi vector
	ld	a,b;		sector multiple
	ld	bc,128*256+data; b=sector length, c=data port
	bit	0,a;		if 0 then 256 or 512 bytes/sector
	jr	nz,actn;	b set for 128 or 384 bytes/sector
	ld	b,0;		b set for 256 or 512 bytes/sector
actn:	cp	1;		compute entry point 1st or 2nd loop
	push	psw;		save as Z flag
	ld	a,e;		i/o command
	cp	wrtcmd;		a write?
	jr	z,wstart;	start write command
;	"	"
	out	(cmnd),a;	fall through to read loop
	pop	psw
	jr	z,rl2
rl1:	halt;			wait for controller
	ini
	jr	nz,rl1
rl2:	halt
	ini
	jr	nz,rl2
	jr	done;		read loop done, exit
;
wstart:	out	(cmnd),a;	write loop
	pop	psw
	jr	z,wl2
wl1:	halt
	outi
	jr	nz,wl1
wl2:	halt
	outi
	jr	nz,wl2
;	 "	 "
done:	pop	af;		byte at nmi vector address
	ld	(nmivec),a;	restore it
	in	a,(bitport);	turn rom back on
	or	bankbit
	out	(bitport),a
	ei;			turn interrupts on
	call	busy;		get status when contoller not busy
	and	d;		status mask
	jp	nz,saverr;	If soft error record it & exit
	ret;			with any non-zero error code
;
; This section defines the disk parameters
; (dph's are images moved to RAM)
.dpha:	dw	0,0,0,0;	dph for unit A:
	dw	dirbuf,dpbd;	directory buffer, Disk Param. Block
	dw	csva, alva;	check sum pointer, alloc. map ptr
	db	ddbit;		density flag for this drive
;
.dphb:	dw	0,0,0,0;	dph for unit B:
	dw	dirbuf,dpbd;	directory buffer, Disk Param. Block
	dw	csvb, alvb;	check sum pointer, alloc. map ptr.
	db	ddbit;		density flag for this drive
;
; ( single density );
.dpbs:	dw	18;		(spt) sectors per track
	db	3;		(bsh) block shift factor
	db	7;		(blm) block mask
	db	0;		(exm) extent mask
	dw	82;		(dsm) max logical block #
	dw	31;		(drm) max directory #
	db	80H;		(al0) directory allocation map
	db	00H;		(al1)
	dw	8;		(cks) size of dir. check vector
	dw	3;		(off) reserved tracks
;
; ( single sided/double density ) moved in as needed
.dpbd:	dw	40;		(spt) sectors per track
	db	3;		(bsh) block shift factor
	db	7;		(blm) block mask
	db	0;		(exm) extent mask
	dw	194;		(dsm) max logical block #
	dw	63;		(drm) max directory #
	db	0F0H;		(al0) dir. alloc. map/BIOS space
	db	00H;		(al1)
	dw	16;		(cks) size of directory check vector
	dw	1;		(off) reserved tracks
;
; sector interleave table  ( single density ). Kept in RAM
.tbl1:	db	1,6,11,16
	db	3,8,13,18
	db	5,10,15,2
	db	7,12,17,4
	db	9,14
;
.imgend:
imaglen	equ	.imgend-ioimage;	length of this image
;
; Following only initialized on cold boot (power on)
.ckwrt:	db	0ffh;		initializer, check for good writes
.rtry1:	db	tries1;			(0th table entry special)
.rtry2:	db	tries2;			initial error retry counts
.adata:	db	0,0,0;		last error and soft error counts
.bdata:	db	0,0,0;		and the same for the "b" drive
.ckend:
;
; ( double sided/double density). Moved in as needed
.dsdd:	dw	40;		(spt) sectors per track
	db	4;		(bsh) block shift factor
	db	0fh;		(blm) block mask
	db	1;		(exm) extent mask
	dw	196;		(dsm) max logical block
	dw	63;		(drm) max directory #
	db	0c0h;		(al0) dir. alloc. map & bios space
	db	0;		(al1)
	dw	16;		(cks) size of directory check vector
	dw	1;		(off) reserved tracks
;
; ----------------------------------------------------------
; NOTE: the data segment is placed after the code segment 
; because storage lengths depend on the code to be moved in
; ----------------------------------------------------------
	dseg
;
;
; Disk operations - requested values
sekdsk:	ds	1;	disk requested
sektrk:	ds	2;	track number
seksec:	ds	1;	sector number
;
dsk:	ds	1;	current disk drive
ctrack: ds	1;	track number (real) for current drive
denflag: ds	1;	density flag for current drive
sidflg:	ds	1
tracka:	ds	3;	Drive A track (255 means density unknown)
trackb:	ds	3;	Drive B track (255 means density unknown)
csva:	ds	16;	Drive A directory check
alva:	ds	26;	Drive A allocation map
csvb:	ds	16;	Drive B directory check
alvb:	ds	26;	Drive B allocation map
;
;	Routines inserted on power-on start
; ** THIS AREA MUST MATCH THE CODE ABOVE, moved in **
;
move:	ds	.rd-.move;	move mem blocks, callable from rom
rd:	ds	.wrt-.rd;	read physical sector size b, to de^
wrt:	ds	.dpha-.wrt;	write physical sect size b from de^
;	END of installed routines
;
; Disk drive stuff, initialized on power-on start
;
; Disk paramater blocks etc
dpha:	ds	.dphb-.dpha;	dph for A
dphb:	ds	.dpbs-.dphb;	dph for B
dpbs:	ds	.dpbd-.dpbs;	single density disk param blk
dpbd:	ds	.tbl1-.dpbd;	double density disk param blk
tbl1:	ds	.imgend-.tbl1;	single density skew table
;
; Any disk error parameters follow CHKWRT.  HOME returns a pointer
; to chkwrt (in hl), to allow external systems to modify. 
; An unmodified Kaypro returns a pointer to page 0, so we can
; tell them apart.
; MAKE SURE these agree with declaration from .chkwrt on in code
chkwrt:	ds	1;		init true, check for good writes
rtry1:	ds	1
rtry2:	ds	1
;
; Following counts etc measured from last cold start time
aerr:	ds	1;		last soft error on "a"
aerrct:	ds	2;		count of soft errors on "a"
berr:	ds	1;		last soft error on "b"
berrct:	ds	2;		count of soft errors on "b"
; Can add further disk drives here.  Use only for this structure
;
; ** ------- END of moved in area --------- **
;
; Storage
dsksns:	ds	6;	buffer for disk trk/adr data
;
dirbuf:	ds	128;	CP/m directory buffer
;
	end